use serde_json;
use std::fmt;
use super::utils::deserialize_u16;
use super::*;
use internal::prelude::*;
use model::misc::Mentionable;

#[cfg(feature = "model")]
use chrono::NaiveDateTime;
#[cfg(feature = "model")]
use std::fmt::Write;
#[cfg(feature = "model")]
use std::mem;
#[cfg(feature = "cache")]
use std::sync::{Arc, RwLock};
#[cfg(feature = "model")]
use builder::{CreateMessage, EditProfile};
#[cfg(feature = "cache")]
use CACHE;
#[cfg(feature = "model")]
use http::{self, GuildPagination};

/// Information about the current user.
#[derive(Clone, Debug, Deserialize)]
pub struct CurrentUser {
    pub id: UserId,
    pub avatar: Option<String>,
    #[serde(default)]
    pub bot: bool,
    #[serde(deserialize_with = "deserialize_u16")]
    pub discriminator: u16,
    pub email: Option<String>,
    pub mfa_enabled: bool,
    #[serde(rename = "username")]
    pub name: String,
    pub verified: bool,
}

#[cfg(feature = "model")]
impl CurrentUser {
    /// Returns the formatted URL of the user's icon, if one exists.
    ///
    /// This will produce a WEBP image URL, or GIF if the user has a GIF avatar.
    ///
    /// # Examples
    ///
    /// Print out the current user's avatar url if one is set:
    ///
    /// ```rust,no_run
    /// # use serenity::client::CACHE;
    /// #
    /// # let cache = CACHE.read().unwrap();
    /// #
    /// // assuming the cache has been unlocked
    /// let user = &cache.user;
    ///
    /// match user.avatar_url() {
    ///     Some(url) => println!("{}'s avatar can be found at {}", user.name, url),
    ///     None => println!("{} does not have an avatar set.", user.name)
    /// }
    /// ```
    #[inline]
    pub fn avatar_url(&self) -> Option<String> { avatar_url(self.id, self.avatar.as_ref()) }

    /// Returns the formatted URL to the user's default avatar URL.
    ///
    /// This will produce a PNG URL.
    #[inline]
    pub fn default_avatar_url(&self) -> String { default_avatar_url(self.discriminator) }

    /// Edits the current user's profile settings.
    ///
    /// This mutates the current user in-place.
    ///
    /// Refer to `EditProfile`'s documentation for its methods.
    ///
    /// # Examples
    ///
    /// Change the avatar:
    ///
    /// ```rust,ignore
    /// use serenity::CACHE;
    ///
    /// let avatar = serenity::utils::read_image("./avatar.png").unwrap();
    ///
    /// CACHE.write().unwrap().user.edit(|p| p.avatar(Some(&avatar)));
    /// ```
    pub fn edit<F>(&mut self, f: F) -> Result<()>
        where F: FnOnce(EditProfile) -> EditProfile {
        let mut map = Map::new();
        map.insert("username".to_owned(), Value::String(self.name.clone()));

        if let Some(email) = self.email.as_ref() {
            map.insert("email".to_owned(), Value::String(email.clone()));
        }

        match http::edit_profile(&f(EditProfile(map)).0) {
            Ok(new) => {
                let _ = mem::replace(self, new);

                Ok(())
            },
            Err(why) => Err(why),
        }
    }

    /// Retrieves the URL to the current user's avatar, falling back to the
    /// default avatar if needed.
    ///
    /// This will call [`avatar_url`] first, and if that returns `None`, it
    /// then falls back to [`default_avatar_url`].
    ///
    /// [`avatar_url`]: #method.avatar_url
    /// [`default_avatar_url`]: #method.default_avatar_url
    pub fn face(&self) -> String {
        self.avatar_url()
            .unwrap_or_else(|| self.default_avatar_url())
    }

    /// Gets a list of guilds that the current user is in.
    ///
    /// # Examples
    ///
    /// Print out the names of all guilds the current user is in:
    ///
    /// ```rust,no_run
    /// # use serenity::client::CACHE;
    /// #
    /// # let cache = CACHE.read().unwrap();
    /// #
    /// // assuming the cache has been unlocked
    /// let user = &cache.user;
    ///
    /// if let Ok(guilds) = user.guilds() {
    ///     for (index, guild) in guilds.into_iter().enumerate() {
    ///         println!("{}: {}", index, guild.name);
    ///     }
    /// }
    /// ```
    pub fn guilds(&self) -> Result<Vec<GuildInfo>> {
        http::get_guilds(&GuildPagination::After(GuildId(1)), 100)
    }

    /// Returns the invite url for the bot with the given permissions.
    ///
    /// This queries the REST API for the client id.
    ///
    /// If the permissions passed are empty, the permissions part will be dropped.
    ///
    /// # Examples
    ///
    /// Get the invite url with no permissions set:
    ///
    /// ```rust,no_run
    /// # use serenity::client::CACHE;
    /// #
    /// # let mut cache = CACHE.write().unwrap();
    ///
    /// use serenity::model::permissions::Permissions;
    ///
    /// // assuming the cache has been unlocked
    /// let url = match cache.user.invite_url(Permissions::empty()) {
    ///     Ok(v) => v,
    ///     Err(why) => {
    ///         println!("Error getting invite url: {:?}", why);
    ///
    ///         return;
    ///     },
    /// };
    ///
    /// assert_eq!(url, "https://discordapp.com/api/oauth2/authorize?client_id=249608697955745802&scope=bot");
    /// ```
    ///
    /// Get the invite url with some basic permissions set:
    ///
    /// ```rust,no_run
    /// # use serenity::client::CACHE;
    /// #
    /// # let mut cache = CACHE.write().unwrap();
    ///
    /// use serenity::model::permissions::*;
    ///
    /// // assuming the cache has been unlocked
    /// let url = match cache.user.invite_url(READ_MESSAGES | SEND_MESSAGES | EMBED_LINKS) {
    ///     Ok(v) => v,
    ///     Err(why) => {
    ///         println!("Error getting invite url: {:?}", why);
    ///
    ///         return;
    ///     },
    /// };
    ///
    /// assert_eq!(url,
    /// "https://discordapp.
    /// com/api/oauth2/authorize?client_id=249608697955745802&scope=bot&permissions=19456");
    /// ```
    ///
    /// # Errors
    ///
    /// Returns an
    /// [`HttpError::InvalidRequest(Unauthorized)`][`HttpError::InvalidRequest`]
    /// If the user is not authorized for this end point.
    ///
    /// May return [`Error::Format`] while writing url to the buffer.
    ///
    /// [`Error::Format`]: ../enum.Error.html#variant.Format
    /// [`HttpError::InvalidRequest`]: ../http/enum.HttpError.html#variant.InvalidRequest
    pub fn invite_url(&self, permissions: Permissions) -> Result<String> {
        let bits = permissions.bits();
        let client_id = match http::get_current_application_info() {
            Ok(v) => v.id,
            Err(e) => return Err(e),
        };

        let mut url = format!(
            "https://discordapp.com/api/oauth2/authorize?client_id={}&scope=bot",
            client_id
        );

        if bits != 0 {
            write!(url, "&permissions={}", bits)?;
        }

        Ok(url)
    }

    /// Returns a static formatted URL of the user's icon, if one exists.
    ///
    /// This will always produce a WEBP image URL.
    ///
    /// # Examples
    ///
    /// Print out the current user's static avatar url if one is set:
    ///
    /// ```rust,no_run
    /// # use serenity::client::CACHE;
    /// #
    /// # let cache = CACHE.read().unwrap();
    /// #
    /// // assuming the cache has been unlocked
    /// let user = &cache.user;
    ///
    /// match user.static_avatar_url() {
    ///     Some(url) => println!("{}'s static avatar can be found at {}", user.name, url),
    ///     None => println!("Could not get static avatar for {}.", user.name)
    /// }
    /// ```
    #[inline]
    pub fn static_avatar_url(&self) -> Option<String> {
        static_avatar_url(self.id, self.avatar.as_ref())
    }

    /// Returns the tag of the current user.
    ///
    /// # Examples
    ///
    /// Print out the current user's distinct identifier (e.g., Username#1234):
    ///
    /// ```rust,no_run
    /// # use serenity::client::CACHE;
    /// #
    /// # let cache = CACHE.read().unwrap();
    /// #
    /// // assuming the cache has been unlocked
    /// println!("The current user's distinct identifier is {}", cache.user.tag());
    /// ```
    #[inline]
    pub fn tag(&self) -> String { tag(&self.name, self.discriminator) }
}

/// An enum that represents a default avatar.
///
/// The default avatar is calculated via the result of `discriminator % 5`.
///
/// The has of the avatar can be retrieved via calling [`name`] on the enum.
///
/// [`name`]: #method.name
#[derive(Copy, Clone, Debug, Deserialize, Hash, Eq, PartialEq, PartialOrd, Ord, Serialize)]
pub enum DefaultAvatar {
    /// The avatar when the result is `0`.
    #[serde(rename = "6debd47ed13483642cf09e832ed0bc1b")]
    Blurple,
    /// The avatar when the result is `1`.
    #[serde(rename = "322c936a8c8be1b803cd94861bdfa868")]
    Grey,
    /// The avatar when the result is `2`.
    #[serde(rename = "dd4dbc0016779df1378e7812eabaa04d")]
    Green,
    /// The avatar when the result is `3`.
    #[serde(rename = "0e291f67c9274a1abdddeb3fd919cbaa")]
    Orange,
    /// The avatar when the result is `4`.
    #[serde(rename = "1cbd08c76f8af6dddce02c5138971129")]
    Red,
}

impl DefaultAvatar {
    /// Retrieves the String hash of the default avatar.
    pub fn name(&self) -> Result<String> { serde_json::to_string(self).map_err(From::from) }
}

enum_number!(
    /// Identifier for the notification level of a channel.
    NotificationLevel {
        /// Receive notifications for everything.
        All = 0,
        /// Receive only mentions.
        Mentions = 1,
        /// Receive no notifications.
        Nothing = 2,
        /// Inherit the notification level from the parent setting.
        Parent = 3,
    }
);

/// The representation of a user's status.
///
/// # Examples
///
/// - [`DoNotDisturb`];
/// - [`Invisible`].
///
/// [`DoNotDisturb`]: #variant.DoNotDisturb
/// [`Invisible`]: #variant.Invisible
#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, PartialOrd, Ord, Serialize)]
pub enum OnlineStatus {
    #[serde(rename = "dnd")]
    DoNotDisturb,
    #[serde(rename = "idle")]
    Idle,
    #[serde(rename = "invisible")]
    Invisible,
    #[serde(rename = "offline")]
    Offline,
    #[serde(rename = "online")]
    Online,
}

impl OnlineStatus {
    pub fn name(&self) -> &str {
        match *self {
            OnlineStatus::DoNotDisturb => "dnd",
            OnlineStatus::Idle => "idle",
            OnlineStatus::Invisible => "invisible",
            OnlineStatus::Offline => "offline",
            OnlineStatus::Online => "online",
        }
    }
}

impl Default for OnlineStatus {
    fn default() -> OnlineStatus { OnlineStatus::Online }
}

/// Information about a user.
#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Hash)]
pub struct User {
    /// The unique Id of the user. Can be used to calculate the account's
    /// cration date.
    pub id: UserId,
    /// Optional avatar hash.
    pub avatar: Option<String>,
    /// Indicator of whether the user is a bot.
    #[serde(default)]
    pub bot: bool,
    /// The account's discriminator to differentiate the user from others with
    /// the same [`name`]. The name+discriminator pair is always unique.
    ///
    /// [`name`]: #structfield.name
    #[serde(deserialize_with = "deserialize_u16")]
    pub discriminator: u16,
    /// The account's username. Changing username will trigger a discriminator
    /// change if the username+discriminator pair becomes non-unique.
    #[serde(rename = "username")]
    pub name: String,
}

#[cfg(feature = "model")]
impl User {
    /// Returns the formatted URL of the user's icon, if one exists.
    ///
    /// This will produce a WEBP image URL, or GIF if the user has a GIF avatar.
    #[inline]
    pub fn avatar_url(&self) -> Option<String> { avatar_url(self.id, self.avatar.as_ref()) }

    /// Creates a direct message channel between the [current user] and the
    /// user. This can also retrieve the channel if one already exists.
    ///
    /// [current user]: struct.CurrentUser.html
    #[inline]
    pub fn create_dm_channel(&self) -> Result<PrivateChannel> { self.id.create_dm_channel() }

    /// Retrieves the time that this user was created at.
    #[inline]
    pub fn created_at(&self) -> NaiveDateTime { self.id.created_at() }

    /// Returns the formatted URL to the user's default avatar URL.
    ///
    /// This will produce a PNG URL.
    #[inline]
    pub fn default_avatar_url(&self) -> String { default_avatar_url(self.discriminator) }

    /// Sends a message to a user through a direct message channel. This is a
    /// channel that can only be accessed by you and the recipient.
    ///
    /// # Examples
    ///
    /// When a user sends a message with a content of `"~help"`, DM the author a
    /// help message, and then react with `'👌'` to verify message sending:
    ///
    /// ```rust,no_run
    /// # use serenity::prelude::*;
    /// # use serenity::model::*;
    /// #
    /// use serenity::model::Permissions;
    /// use serenity::CACHE;
    ///
    /// struct Handler;
    ///
    /// impl EventHandler for Handler {
    ///     fn on_message(&self, _: Context, msg: Message) {
    ///         if msg.content == "~help" {
    ///             let url = match CACHE.read() {
    ///                 Ok(v) => {
    ///                     match v.user.invite_url(Permissions::empty()) {
    ///                         Ok(v) => v,
    ///                         Err(why) => {
    ///                             println!("Error creating invite url: {:?}", why);
    ///
    ///                             return;
    ///                         },
    ///                     }
    ///                 },
    ///                 Err(why) => {
    ///                     println!("Error reading from CACHE: {:?}", why);
    ///
    ///                     return;
    ///                 }
    ///             };
    /// let help = format!("Helpful info here. Invite me with this link: <{}>",
    /// url);
    ///
    ///             match msg.author.direct_message(|m| m.content(&help)) {
    ///                 Ok(_) => {
    ///                     let _ = msg.react('👌');
    ///                 },
    ///                 Err(why) => {
    ///                     println!("Err sending help: {:?}", why);
    ///
    ///                     let _ = msg.reply("There was an error DMing you help.");
    ///                 },
    ///             };
    ///         }
    ///     }
    /// }
    ///
    /// let mut client = Client::new("token", Handler);
    /// ```
    ///
    /// # Examples
    ///
    /// Returns a [`ModelError::MessagingBot`] if the user being direct messaged
    /// is a bot user.
    ///
    /// [`ModelError::MessagingBot`]: enum.ModelError.html#variant.MessagingBot
    /// [`PrivateChannel`]: struct.PrivateChannel.html
    /// [`User::dm`]: struct.User.html#method.dm
    // A tale with Clippy:
    //
    // A person named Clippy once asked you to unlock a box and take something
    // from it, but you never re-locked it, so you'll die and the universe will
    // implode because the box must remain locked unless you're there, and you
    // can't just borrow that item from it and take it with you forever.
    //
    // Instead what you do is unlock the box, take the item out of it, make a
    // copy of said item, and then re-lock the box, and take your copy of the
    // item with you.
    //
    // The universe is still fine, and nothing implodes.
    //
    // (AKA: Clippy is wrong and so we have to mark as allowing this lint.)
    #[allow(let_and_return)]
    #[cfg(feature = "builder")]
    pub fn direct_message<F>(&self, f: F) -> Result<Message>
        where F: FnOnce(CreateMessage) -> CreateMessage {
        if self.bot {
            return Err(Error::Model(ModelError::MessagingBot));
        }

        let private_channel_id = feature_cache! {{
            let finding = {
                let cache = CACHE.read().unwrap();

                let finding = cache.private_channels
                    .values()
                    .map(|ch| ch.read().unwrap())
                    .find(|ch| ch.recipient.read().unwrap().id == self.id)
                    .map(|ch| ch.id);

                finding
            };

            if let Some(finding) = finding {
                finding
            } else {
                let map = json!({
                    "recipient_id": self.id.0,
                });

                http::create_private_channel(&map)?.id
            }
        } else {
            let map = json!({
                "recipient_id": self.id.0,
            });

            http::create_private_channel(&map)?.id
        }};

        private_channel_id.send_message(f)
    }

    /// This is an alias of [direct_message].
    ///
    /// # Examples
    ///
    /// Sending a message:
    ///
    /// ```rust,ignore
    /// // assuming you are in a context
    ///
    /// let _ = message.author.dm("Hello!");
    /// ```
    ///
    /// # Examples
    ///
    /// Returns a [`ModelError::MessagingBot`] if the user being direct messaged
    /// is a bot user.
    ///
    /// [`ModelError::MessagingBot`]: enum.ModelError.html#variant.MessagingBot
    /// [direct_message]: #method.direct_message
    #[cfg(feature = "builder")]
    #[inline]
    pub fn dm<F: FnOnce(CreateMessage) -> CreateMessage>(&self, f: F) -> Result<Message> {
        self.direct_message(f)
    }

    /// Retrieves the URL to the user's avatar, falling back to the default
    /// avatar if needed.
    ///
    /// This will call [`avatar_url`] first, and if that returns `None`, it
    /// then falls back to [`default_avatar_url`].
    ///
    /// [`avatar_url`]: #method.avatar_url
    /// [`default_avatar_url`]: #method.default_avatar_url
    pub fn face(&self) -> String {
        self.avatar_url()
            .unwrap_or_else(|| self.default_avatar_url())
    }

    /// Check if a user has a [`Role`]. This will retrieve the [`Guild`] from
    /// the [`Cache`] if it is available, and then check if that guild has the
    /// given [`Role`].
    ///
    /// Three forms of data may be passed in to the guild parameter: either a
    /// [`Guild`] itself, a [`GuildId`], or a `u64`.
    ///
    /// # Examples
    ///
    /// Check if a guild has a [`Role`] by Id:
    ///
    /// ```rust,ignore
    /// // Assumes a 'guild' and `role_id` have already been bound
    /// let _ = message.author.has_role(guild, role_id);
    /// ```
    ///
    /// [`Guild`]: struct.Guild.html
    /// [`GuildId`]: struct.GuildId.html
    /// [`Role`]: struct.Role.html
    /// [`Cache`]: ../cache/struct.Cache.html
    // no-cache would warn on guild_id.
    pub fn has_role<G, R>(&self, guild: G, role: R) -> bool
        where G: Into<GuildContainer>, R: Into<RoleId> {
        let role_id = role.into();

        match guild.into() {
            GuildContainer::Guild(guild) => guild.roles.contains_key(&role_id),
            GuildContainer::Id(_guild_id) => {
                feature_cache! {{
                    CACHE.read()
                        .unwrap()
                        .guilds
                        .get(&_guild_id)
                        .map(|g| g.read().unwrap().roles.contains_key(&role_id))
                        .unwrap_or(false)
                } else {
                    true
                }}
            },
        }
    }

    /// Refreshes the information about the user.
    ///
    /// Replaces the instance with the data retrieved over the REST API.
    ///
    /// # Examples
    ///
    /// If maintaing a very long-running bot, you may want to periodically
    /// refresh information about certain users if the state becomes
    /// out-of-sync:
    ///
    /// ```rust,no_run
    /// # use serenity::prelude::*;
    /// # use serenity::model::*;
    /// #
    /// struct Handler;
    ///
    /// impl EventHandler for Handler {
    ///     fn on_message(&self, _: Context, _: Message) {
    ///         // normal message handling here
    ///     }
    /// }
    /// let mut client = Client::new("token", Handler);
    /// #
    /// use serenity::model::UserId;
    /// use serenity::CACHE;
    /// use std::thread;
    /// use std::time::Duration;
    ///
    /// let special_users = vec![UserId(114941315417899012), UserId(87600987040120832)];
    ///
    /// // start a new thread to periodically refresh the special users' data
    /// // every 12 hours
    /// let handle = thread::spawn(move || {
    ///     // 12 hours in seconds
    ///     let duration = Duration::from_secs(43200);
    ///
    ///     loop {
    ///         thread::sleep(duration);
    ///
    ///         let cache = CACHE.read().unwrap();
    ///
    ///         for id in &special_users {
    ///             if let Some(user) = cache.user(*id) {
    ///                 if let Err(why) = user.write().unwrap().refresh() {
    ///                     println!("Error refreshing {}: {:?}", id, why);
    ///                 }
    ///             }
    ///         }
    ///     }
    /// });
    ///
    /// println!("{:?}", client.start());
    /// ```
    pub fn refresh(&mut self) -> Result<()> {
        self.id.get().map(|replacement| {
            mem::replace(self, replacement);

            ()
        })
    }


    /// Returns a static formatted URL of the user's icon, if one exists.
    ///
    /// This will always produce a WEBP image URL.
    #[inline]
    pub fn static_avatar_url(&self) -> Option<String> {
        static_avatar_url(self.id, self.avatar.as_ref())
    }

    /// Returns the "tag" for the user.
    ///
    /// The "tag" is defined as "username#discriminator", such as "zeyla#5479".
    ///
    /// # Examples
    ///
    /// Make a command to tell the user what their tag is:
    ///
    /// ```rust,no_run
    /// # use serenity::prelude::*;
    /// # use serenity::model::*;
    /// #
    /// use serenity::utils::MessageBuilder;
    /// use serenity::utils::ContentModifier::Bold;
    ///
    /// struct Handler;
    ///
    /// impl EventHandler for Handler {
    ///     fn on_message(&self, _: Context, msg: Message) {
    ///         if msg.content == "!mytag" {
    ///             let content = MessageBuilder::new()
    ///                 .push("Your tag is ")
    ///                 .push(Bold + msg.author.tag())
    ///                 .build();
    ///
    ///             let _ = msg.channel_id.say(&content);
    ///         }
    ///     }
    /// }
    /// let mut client = Client::new("token", Handler); client.start().unwrap();
    /// ```
    #[inline]
    pub fn tag(&self) -> String { tag(&self.name, self.discriminator) }
}

impl fmt::Display for User {
    /// Formats a string which will mention the user.
    // This is in the format of: `<@USER_ID>`
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        fmt::Display::fmt(&self.id.mention(), f)
    }
}

#[cfg(feature = "model")]
impl UserId {
    /// Creates a direct message channel between the [current user] and the
    /// user. This can also retrieve the channel if one already exists.
    ///
    /// [current user]: struct.CurrentUser.html
    pub fn create_dm_channel(&self) -> Result<PrivateChannel> {
        let map = json!({
            "recipient_id": self.0,
        });

        http::create_private_channel(&map)
    }

    /// Search the cache for the user with the Id.
    #[cfg(feature = "cache")]
    pub fn find(&self) -> Option<Arc<RwLock<User>>> { CACHE.read().unwrap().user(*self) }

    /// Gets a user by its Id over the REST API.
    ///
    /// **Note**: The current user must be a bot user.
    #[inline]
    pub fn get(&self) -> Result<User> { http::get_user(self.0) }
}

impl From<CurrentUser> for UserId {
    /// Gets the Id of a `CurrentUser` struct.
    fn from(current_user: CurrentUser) -> UserId { current_user.id }
}

impl<'a> From<&'a CurrentUser> for UserId {
    /// Gets the Id of a `CurrentUser` struct.
    fn from(current_user: &CurrentUser) -> UserId { current_user.id }
}

impl From<Member> for UserId {
    /// Gets the Id of a `Member`.
    fn from(member: Member) -> UserId { member.user.read().unwrap().id }
}

impl<'a> From<&'a Member> for UserId {
    /// Gets the Id of a `Member`.
    fn from(member: &Member) -> UserId { member.user.read().unwrap().id }
}

impl From<User> for UserId {
    /// Gets the Id of a `User`.
    fn from(user: User) -> UserId { user.id }
}

impl<'a> From<&'a User> for UserId {
    /// Gets the Id of a `User`.
    fn from(user: &User) -> UserId { user.id }
}

impl fmt::Display for UserId {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fmt::Display::fmt(&self.0, f) }
}

#[cfg(feature = "model")]
fn avatar_url(user_id: UserId, hash: Option<&String>) -> Option<String> {
    hash.map(|hash| {
        let ext = if hash.starts_with("a_") {
            "gif"
        } else {
            "webp"
        };

        cdn!("/avatars/{}/{}.{}?size=1024", user_id.0, hash, ext)
    })
}

#[cfg(feature = "model")]
fn default_avatar_url(discriminator: u16) -> String {
    cdn!("/embed/avatars/{}.png", discriminator % 5u16)
}

#[cfg(feature = "model")]
fn static_avatar_url(user_id: UserId, hash: Option<&String>) -> Option<String> {
    hash.map(|hash| cdn!("/avatars/{}/{}.webp?size=1024", user_id, hash))
}

#[cfg(feature = "model")]
fn tag(name: &str, discriminator: u16) -> String {
    // 32: max length of username
    // 1: `#`
    // 4: max length of discriminator
    let mut tag = String::with_capacity(37);
    tag.push_str(name);
    tag.push('#');
    let _ = write!(tag, "{}", discriminator);

    tag
}